1. Field of the Invention
The present invention relates to a relay communication system that enables computers connected to two different local area networks (LANs) to make communication with each other beyond a wide area network (WAN).
2. Description of the Related Art
Conventionally, a remote maintenance system, which performs, from a remote location, monitoring and maintenance for an electronic instrument installed at home, office or the like, has been put into practical use. By using the remote maintenance system, a service technician at a maintenance company can perform maintenance work for the electronic instrument without visiting the actual location where the electronic instrument is installed. There is a merit that the maintenance company can reduce costs by using the remote maintenance system. Even in the case where a problem with the electronic instrument occurs, the service technician can operate the electronic instrument remotely, thus quickly solving the problem that has occurred. In this way, there is a merit also for a user of the electronic instrument that uses the remote maintenance system.
Japanese Patent Laid-Open Publication No. 2003-223521 discloses a technique for monitoring, from a remote location, an operation control device that controls an air conditioner. The maintenance company of the air conditioner purchases a recording medium, in which monitoring software, a password for accessing the operation control device, and the like are recorded, from the manufacturer of the air conditioner in order to acquire monitoring data of the air conditioner from the operation control device.
The maintenance company accesses the operation control device by using the password recorded in the recording medium, and acquires the monitoring data from the operation control device by using the monitoring software. In the case where abnormalities are found in the operation control device when analyzing the monitoring data, the maintenance company performs remote maintenance for the operation control device.
However, timing at which an access right to the operation control device can be set for the maintenance company is limited to the time when the maintenance company purchases the recording medium. Even in the case where the maintenance company is replaced, there is a concern that the previous maintenance company may illegally access the operation control device by using the password recorded in the recording medium.
Moreover, in the case where the maintenance company continuously accesses the operation control device for a long time, there is a concern that a third party other than the service technician may access the operation control device.
Furthermore, the maintenance company cannot confirm the abnormalities that have occurred in the operation control device, until the monitoring data is analyzed. Therefore, it has been difficult to quickly deal with the abnormalities that have occurred in the operation control device.